As you may notice the css selector which is used is .first.second, so no spaces between them.

This way you can assure that only the element which has class first and second will meet the criteria and will be colorized in red. This notation works with ID’s as well, but basically if you have ID, then you know what is the exact element, so it’s useless, but for selection of two classes I think it really useful.

I would like to know if somebody knew about this way of selecting elements?